Peng Zhang , Hegoi Manzano , Ming-Feng Kai , Jian-Guo Dai
{"title":"封闭在 C-S-H 夹层内的水的行为和影响:淬火固体密度泛函理论研究","authors":"Peng Zhang , Hegoi Manzano , Ming-Feng Kai , Jian-Guo Dai","doi":"10.1016/j.cemconres.2024.107600","DOIUrl":null,"url":null,"abstract":"<div><p>Water confined within cement paste significantly influences the material's physical and chemical behaviors. Using quenched solid density functional theory (QSDFT), we investigate the complex behaviors of water confined within C-S-H interlayers. Confined water exists in forms of double layers (0–0.29 nm pores), three layers (0.32–0.59 nm pores), and multiple layers (≥0.65 nm pores). The adsorption isotherms reveal distinct adsorption behaviors depending on the pore size. For pores smaller than 0.59 nm, adsorption occurs as monolayer water adsorption and phase transition. In contrast, larger pores exhibit three stages: monolayer adsorption, multilayer adsorption, and phase transition. The pore pressure is positive for smaller pores (≤0.03 nm) and negative for larger pores; however, after the phase transition, the negative pressure is released with increasing relative humidity (RH). Additionally, temperature increase reduces the adsorption capacity, disrupts the water ordering, shortens the phase transition period, and affects the saturated pore pressure.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":null,"pages":null},"PeriodicalIF":10.9000,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Behaviors and influences of water confined within the C-S-H interlayer: A quenched solid density functional theory study\",\"authors\":\"Peng Zhang , Hegoi Manzano , Ming-Feng Kai , Jian-Guo Dai\",\"doi\":\"10.1016/j.cemconres.2024.107600\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Water confined within cement paste significantly influences the material's physical and chemical behaviors. Using quenched solid density functional theory (QSDFT), we investigate the complex behaviors of water confined within C-S-H interlayers. Confined water exists in forms of double layers (0–0.29 nm pores), three layers (0.32–0.59 nm pores), and multiple layers (≥0.65 nm pores). The adsorption isotherms reveal distinct adsorption behaviors depending on the pore size. For pores smaller than 0.59 nm, adsorption occurs as monolayer water adsorption and phase transition. In contrast, larger pores exhibit three stages: monolayer adsorption, multilayer adsorption, and phase transition. The pore pressure is positive for smaller pores (≤0.03 nm) and negative for larger pores; however, after the phase transition, the negative pressure is released with increasing relative humidity (RH). Additionally, temperature increase reduces the adsorption capacity, disrupts the water ordering, shortens the phase transition period, and affects the saturated pore pressure.</p></div>\",\"PeriodicalId\":266,\"journal\":{\"name\":\"Cement and Concrete Research\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":10.9000,\"publicationDate\":\"2024-07-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Cement and Concrete Research\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0008884624001819\",\"RegionNum\":1,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CONSTRUCTION & BUILDING TECHNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cement and Concrete Research","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0008884624001819","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
Behaviors and influences of water confined within the C-S-H interlayer: A quenched solid density functional theory study
Water confined within cement paste significantly influences the material's physical and chemical behaviors. Using quenched solid density functional theory (QSDFT), we investigate the complex behaviors of water confined within C-S-H interlayers. Confined water exists in forms of double layers (0–0.29 nm pores), three layers (0.32–0.59 nm pores), and multiple layers (≥0.65 nm pores). The adsorption isotherms reveal distinct adsorption behaviors depending on the pore size. For pores smaller than 0.59 nm, adsorption occurs as monolayer water adsorption and phase transition. In contrast, larger pores exhibit three stages: monolayer adsorption, multilayer adsorption, and phase transition. The pore pressure is positive for smaller pores (≤0.03 nm) and negative for larger pores; however, after the phase transition, the negative pressure is released with increasing relative humidity (RH). Additionally, temperature increase reduces the adsorption capacity, disrupts the water ordering, shortens the phase transition period, and affects the saturated pore pressure.
期刊介绍:
Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.